The court heard she was also often seen to be unusually nervous while scanning her items at the check-outs.
Milner, a single mum the court heard was financially strapped, admitted to shopping with the fraudulent barcodes on 31 occasions.
She further admitted to three aborted attempts.
In court documents obtained by the Daily Mail, it was revealed her scam was finally foiled on September 18 last year, when a Woolworths employee confronted her at the checkout.
Court documents said Milner told the employee she "forgot her wallet" and fled the store.
She left behind three packets of lamb cutlets, one packet of bacon and some Glen 20 disinfectant.
It was Milner's second attempt to go through self-serve after the supermarket manager had earlier spoken to her at the check-outs.
She claimed she forgot something and returned to the supermarket aisles, the police facts state.
Read more: Australian mum admits to stealing $4800 in groceries in elaborate, self-serve checkout scam
But the suspicious woman stayed at the check-outs, awaiting Milner's return.
The Woolworths encounter came just three days after she was nearly busted at a nearby Coles. She scanned a $27.61 rump roast with one of her fake barcodes when a worker noticed, court papers said.
The staff member voided the sale and Milner pleaded ignorance.
She scanned her FlyBuys card and walked out. Police soon after traced her bank card and were granted a warrant.
The 35-year-old's father said she was in "dire financial straits" when she hatched the fraudulent scheme.
"She's a different person now. She has turned her life around," her father said.
Character references submitted to the court gave further insight into why Milner came up with the plan.
"All her problems started when her husband walked out on her and left her with a mortgage (and) a mountain of debt and left her to raise their daughter on their own," her sister Michelle said.
"She is really trying to turn her life around."
Her sister-in-law Lisa said "she made some very bad decisions at a time of desperation" and was a "beautiful, loving, caring, good individual who just made some wrong choices in life".
She said Milner was a very private person who never wanted to burden her family "so she chose to try and do things on her own".
Milner has so far declined to comment.